Ignition point assembly with guide posts for movable contact

ABSTRACT

This invention provides an easily replaceable ignition point assembly that is designed to be operated by the point cam of a conventional distributor of an internal combustion engine. The ignition point assembly comprises a base, a contact arm pivotally mounted on the base for movement toward and away from the base, a stationary contact located on the base for making and breaking electrical engagement with the contact arm, and actuator means projecting through an opening in the base for engaging the contact arm and a cam located on the opposite side of the base from the contact arm to pivot the contact arm into and out of electrical engagement with the stationary contact upon rotation of the cam. Guide posts on the base to engage the contact arm to limit its movement to a perpendicular path.

United States Patent 1191 Mann [ Mar. 19, 1974 1 IGNITION POINT ASSEMBLY WITH GUIDE POSTS FOR MOVABLE CONTACT Eugene H. Mann, 1240 th Ave., North, Naples, Fla. 33940 Filed: Sept. 25, 1972 Appl. No.: 292,249

[7 6] Inventor:

[56] References Cited UNITED STATES PATENTS 12/1965 Nanninga ZOO/3O A 11/1966 Gover ZOO/l9 A 9/1962 Sargis ZOO/ A 5/1965 Hartman, Jr 200/30 A ll/l964 Beardow 200/30 A X i erxc tqrnins fle esR- 5 9 it 7. Attorney, Agent, or Firm-Finnegan, Henderson, Farabow & Garrett 5 7] ABSTRACT This invention provides an easily replaceable ignition point assembly that is designed to be operated by the point cam of a conventional distributor of an internal combustion engine. The ignition point assembly comprises a base, a contact arm pivotally mounted on the base for movement toward and away from the base, a stationary contact located on the base for making and breaking electrical engagement with the contact arm, and actuator means projecting through an opening in the base for engaging the contact arm and a cam located on the opposite side of the base from the contact arm to pivot the contact arm into and out of electrical engagement with the stationary contact upon rotation of the cam. Guide posts on the base to engage the contact arm to limit its movement to a perpendicular path.

11 Claims, 2 Drawing Figures Y 1 3o Q 58 4 2 /64 26 L f 50 l QLNI kL IGNITION POINT ASSEMBLY WITH GUIDE POSTS FOR MOVABLE CONTACT The present invention relates to an ignition point assembly and, more particularly, to an ignition point assembly comprising aset of ignition points and a condenser encased within a hollow, disc-shaped housing to provide an easily replaceable unit.

In the art of distributors for internal combustion engines, it is well known to mount a set of ignition points and a condenser within a distributor housing and to locate a point cam within the housing to operate the ignition points. The replacement of the ignition points and condenser of a conventional distributor requires removal of its distributor cap, disconnection and removal of the distributor from the engine, partial dismantling of the distributor, removal of the old set of ignition points and condenser from the distributor, installation of a new set of ignition points and a condenser, adjustment of the ignition points to factory specifications, replacement of the distributor on the engine, adjustment of ignition timing, and reassembly of the distributor. Thus, the conventional distributor has the disadvantage that it is extremely laborious and time-consuming to replace the ignition points and condenser.

The'present invention is designed to eliminate the time-consuming operation of replacement of the ignition points and condenser of a conventional distributor. The invention provides a single'unit including a set of ignition points and a condenser that can be mounted at a location remote from the distributor housing. The unit is readily replaceable and does not require the dismantling of the distributor orits removal from the engine for replacement of the ignition points and condenser.

In accordance with the present invention, an ignition point assembly comprises a base having an opening extending completely therethrough, a contact arm pivotally mountedon the base for movement toward and away from the base, a stationary contact located on the base for making and breaking electrical engagement with the contact arm, and actuator means projection through the opening in the base for engaging the contact arm and a cam located on the opposite side of the:base from the contact arm to pivot the contact arm into and out of electrical engagement with the stationary contact upon rotation of the cam. A preferred embodiment of the ignition point assembly includes guide means forlimiting the contact arm to movement in a path perpendicular to the base. The preferred embodiment also includes means for normally biasing the contact arm into electrical engagement with the stationary contact.

The accompanying drawing illustrates a preferred embodiment of the invention and, together with the description, serves to explain the principles of the invention.

IN THE DRAWING FIG. 1 is an elevational section illustrating an ignition point assembly constructed according to the principles of the present invention mounted adjacent to a conventional point cam; and

FIG. 2 is a sectional view of the ignition point assembly and point cam taken along line 2-2 of FIG. 1.

Referring to FIG. 1, an ignition point assembly, generally 20, constructed in accordance with the present invention is mounted on support housing 22 constructed of electrically conductive material in which a shaft, 24 is mounted for rotation. A conventional point cam 26 is mounted'on shaft 24. In addition, a distributor (not shown) including a rotary contact driven by shaft 24 and a plurality of stationary contacts mounted for successive engagement with the rotary contact is mounted on the upper end of support housing 22. The support housing is provided with a circular opening 28 surrounded by a flange 30 to facilitate mounting of ignition point assembly 20 on the housing.

The ignition point assembly of the present invention includes a base provided with an opening extending completely through the base. As shown in FIG. I, ignition point assembly 20 includes a flat, generally circular base 32 having a central opening 34. In addition, a dome-shaped cover 36 is formed integrally with base 32 to provide a housing having a hollow interior space. Base 32 and cover 36 are made of non-conductive material.

In accordance with the invention, a contact arm is pivotally mounted on the base for movement toward and away from the base. As shown in the preferred embodiment of FIG. 1, ignition point assembly 20 includes a contact arm 38 located within the interior space of the housing provided by base 32 and dome-shaped cover 36. Contact arm 38 is made of conductive material and includes a rounded end 40 and a contact end 42. The rounded end of contact arm 32 is received in a recess 44 provided in a pivot block 46 formed integrally with base 32. Rounded end 40 of the contact arm and recess 44 constitute a pivotal mounting for the contact arm to allow the arm to move toward and away' from base 32. As shown in FIGS. 1 and 2, a coil wire is connected to contact arm 38 and extends through cover 36 to an ignition coil (not shown).

The ignition point assembly of the present invention also includes a stationary contact located on the base for making and breaking electrical engagement with the contact arm. In the preferred embodiment of FIG.

'1, a contact 48 of conductive material is located on base 32 in alignment with contact end 42 of arm 38. Pivotal movement of contact arm 38 results in movement of its contact end 42 into and out of electrical engagement with contact 48.

In accordance with the invention, the ignition point assembly includes actuator means projecting through the opening in the base for engaging the contact arm and a cam located on the opposite side of the base from the contact arm to pivot the contact arm into and out of electrical engagement with the stationary contact upon rotation of the cam. As shown in the embodiment of FIGS. 1 and 2, the actuator means comprises an elongated cylindrical plunger 50 mounted for axial movement within central opening 34 provided in base 32. Plunger 50 engages the camming surface of point cam 26 and a flat surface 52 provided on contact arm 38.

In a preferred embodiment of the ignition point assembly, guide means is provided for limiting the contact arm to movement in a path perpendicular to the base. In the preferred embodiment of FIGS. 1 and 2, this guide means comprises a pair of spaced guide posts 54 projecting perpendicularly from base 32. Contact arm 38 is received in the space provided between guide posts 54 and is thus guided in a path perpendicular to base 32.

The preferred embodiment of the ignition point assembly also includes means for normally biasing the contact arm into electrical engagement with the stationary contact. In the preferred embodiment of FIGS. 1 and 2, this means comprises a spring 56 located between the dome-shaped cover 36 and contact arm 38 for urging the contact arm toward base 32 to normally maintain its contact end 42 in electrical engagement with contact 48.

As shown in FIGS. 1 and 2, ignition point assembly is provided with a flange 58 formed at the periphery of base 32 to facilitate mounting of the ignition point assembly adjacent to point cam 26. Flange 58 is provided with a plurality of spaced openings for receiving a set of threaded bolts 60 for securing ignition point assembly 20 to flange of support housing 22. An additional flange 62 is formed on base 32 and received within opening 28 of the support housing to provide for secure mounting of the ignition point assembly on the support housing.

In addition, as shown in FIG. 2, a condenser 64 is located within the interior space of the housing provided by base 32 and dome-shaped cover 36 in a position adjacent to contact arm 38. Condenser 64 is mounted on a support 66 formed as an integral part of base 32. The condenser includes a first conductor 68 connected to contact arm 38 and a second conductor 70 connected to ground via one of bolts 60 and support housing 22. A ground lead 72 (FIG. 2) also connects stationary contact 48 to ground via one of bolts 60 and housing 22.

In operation, rotation of shaft 24 and cam 26 results in pivotal movement of contact arm 38 on its rounded end 40. When plunger 50 is in contact with a flat portion of the camming surface of point cam 26, contact arm 38 is biased toward base 32 by spring 56 to move contact end 42 of the arm into electrical engagement with contact 48. The voltage across condenser 64 is thus applied to contact 48. When the cam rotates to a position where one of its corners is in contact with plunger 50, contact arm 38 is pivoted on its rounded end 40 against the action of spring 56 to move its contact end 42 out of electrical engagement with contact 48. Since, as shown in FIG. 2, the camming surface of point cam 26 has a hexagonal configuration, contact end 42 of arm 38 will make and break electrical engagement with contact 48 six times for every revolution of shaft 24 and point cam 26. The configuration of the camming surface of the point cam can be modifled to accomplish more or less contact engagements per revolution of the cam as desired.

When it is necessary to replace ignition point assembly 20, replacement is easily accomplished by unthreading bolts 60, removing the old ignition point assembly from housing 22, and securing a new ignition point assembly to the housing by the bolts. The ignition point assembly is precisely adjusted at the time of its manufacture and, as a result, there is no need for any further adjustment of the ignition point assembly upon installation. The present invention thus provides an ignition point assembly which is extremely simple to replace and elminates the laborious and time-consuming operations required in replacement of conventional distributors.

The invention in its broader aspects is not limited to the specific details shown and described, and modifications may be made in the details of the ignition point assembly without departing from the principles of the present invention.

What is claimed is:

1. An ignition point assembly, comprising:

a non-conductive base having an opening extending completely therethrough;

a contact arm pivotally mounted on said base for movement toward and away from said base;

a stationary contact located on said base for making and breaking electrical engagement with said contact arm;

actuator means projecting through said opening in said base for engaging said contact arm and a cam located on the opposite side of said base from said contact arm to pivot said contact arm into and out of electrical engagement with said stationary contact upon rotation of the cam; and

guide means on said base for engaging said contact arm to limit said arm to pivotal movement in a path perpendicular to said base.

2. The ignition point assembly of claim 1, wherein said guide means comprises:

a pair of spaced guide posts projecting perpendicularly from said base for receiving said contact arm therebetween.

3. The ignition point assembly of claim 1, which includes:

means for normally biasing said contact arm into electrical engagement with said stationary contact.

4. The ignition point assembly of claim 1, wherein said actuator means comprises:

a plunger removably mounted in said opening and interposed between said contact arm and the cam to convert rotary motion of the cam into pivotal movement of said contact arm.

5. An ignition point assembly, comprising:

a non-conductive housing including a flat, generally circular base and a cover extending over said base to define an interior space therebetween, said base having a central opening extending therethrough into said interior space;

a contact arm located within said interior space having a first end pivotally mounted on said housing and a second contact end capable of movement toward and away from said base;

a stationary contact located on said base in alignment with said contact end of said arm for making and breaking electrical engagement with said contact end;

a plunger projecting through said opening in said base for engaging said arm and a point cam located on the opposite side of said base from said arm to pivot said arm to move its contact end into and out of electrical engagement with said stationary contact upon rotation of the point cam; and

guide means on said housing for engaging said contact arm to limit its contact end to movement in a path perpendicular to said base.

6. The ignition point assembly of claim 5, wherein said guide means comprises:

a pair of spaced guide posts projecting perpendicularly from said base for receiving said arm therebetween.

7. The ignition point assembly of claim 5, which includes:

6 means for normally biasing said contact end of said 10. The ignition point assembly of claim 5, which inarm into electrical engagement with said stationary el d f D a peripheral flange extending from said base to facili- 8. The ignition point assembly of claim 7, wherein tate mounting of the ignition point assembly adja said biasing means comprises: 5

cent to the point cam.

a spring located between said cover and said arm for 11 The ignition point assembly of claim 5 wherein urging said arm toward said base to normally maintain its contact end in electrical engagement with Said Stationary Contact said first end of said arm is rounded; and

The ignition point assembly of claim 5, which 10 said base includes a pivotal block having a recess for d receiving said rounded end of said arm to provide a condenser located within said interior space and a pivo al mounting for Said arm. electrically connected to said contact arm. 

1. An ignition point assembly, comprising: a non-conductive base having an opening extending completely therethrough; a contact arm pivotally mounted on said base for movement toward and away from said base; a stationary contact located on said base for making and breaking electrical engagement with said contact arm; actuator means projecting through said opening in said base for engaging said contact arm and a cam located on the opposite side of said base from said contact arm to pivot said contact arm into and Out of electrical engagement with said stationary contact upon rotation of the cam; and guide means on said base for engaging said contact arm to limit said arm to pivotal movement in a path perpendicular to said base.
 2. The ignition point assembly of claim 1, wherein said guide means comprises: a pair of spaced guide posts projecting perpendicularly from said base for receiving said contact arm therebetween.
 3. The ignition point assembly of claim 1, which includes: means for normally biasing said contact arm into electrical engagement with said stationary contact.
 4. The ignition point assembly of claim 1, wherein said actuator means comprises: a plunger removably mounted in said opening and interposed between said contact arm and the cam to convert rotary motion of the cam into pivotal movement of said contact arm.
 5. An ignition point assembly, comprising: a non-conductive housing including a flat, generally circular base and a cover extending over said base to define an interior space therebetween, said base having a central opening extending therethrough into said interior space; a contact arm located within said interior space having a first end pivotally mounted on said housing and a second contact end capable of movement toward and away from said base; a stationary contact located on said base in alignment with said contact end of said arm for making and breaking electrical engagement with said contact end; a plunger projecting through said opening in said base for engaging said arm and a point cam located on the opposite side of said base from said arm to pivot said arm to move its contact end into and out of electrical engagement with said stationary contact upon rotation of the point cam; and guide means on said housing for engaging said contact arm to limit its contact end to movement in a path perpendicular to said base.
 6. The ignition point assembly of claim 5, wherein said guide means comprises: a pair of spaced guide posts projecting perpendicularly from said base for receiving said arm therebetween.
 7. The ignition point assembly of claim 5, which includes: means for normally biasing said contact end of said arm into electrical engagement with said stationary contact.
 8. The ignition point assembly of claim 7, wherein said biasing means comprises: a spring located between said cover and said arm for urging said arm toward said base to normally maintain its contact end in electrical engagement with said stationary contact.
 9. The ignition point assembly of claim 5, which includes: a condenser located within said interior space and electrically connected to said contact arm.
 10. The ignition point assembly of claim 5, which includes: a peripheral flange extending from said base to facilitate mounting of the ignition point assembly adjacent to the point cam.
 11. The ignition point assembly of claim 5, wherein: said first end of said arm is rounded; and said base includes a pivotal block having a recess for receiving said rounded end of said arm to provide a pivotal mounting for said arm. 